Depends what you consider "big name", I'd say Tristan Taormino. Although most of my favorite sex educators are "small time"
Although, honestly I'd rather give point out a "big name" sex educator I hate with a searing passion. Ian Kerner, aka the man that tries to tell me my orgasms aren't "genuine" but a “technique” "lacking a true basis in physiological" and that under no circumstances should we confuse his nonsense definition of my orgasms (and the misinterpretations, improper citing and faulty logic he use to reach that conclusion) with an accurate definition; see any time he discuss male multiple orgasms. And that not the only nonsense: link
the comes out of his mouth.
Honestly, I going to say this bluntly seeing the amount of sex educators that are seemly proud to work alongside this idiot makes me question the credibility of sex educators as a whole. Sure there are individual sex educators I trust, which after read Ian's drivel the first test of which is sadly “will they recognize that when I say orgasm I mean fucking orgasm!”. But as a whole, If I can’t at a minimum be assured that if a walk in to a high profile sex educator's office and being assured my orgasms will be treat as I don’t I don’t know orgasms, them we have a fucking problem. When no one except me seems to be pointing out the idiocy of how Ian approaches atypical male orgasm patterns we have a problem. If Ian Kerner is indicative of the average sex educator, then we have a big fucking problem.